Grobenn25 built an interactive LED handrail system using an Arduino that monitors a large array of infrared sensors to detect what step the user is on. Based on the current detection pattern the stairs will light the LEDs under the handrail appropriately. During the production he looked at many different types of systems and settled on this overkill system. The sensors are changing their detection parameters constantly so that ambient lighting conditions will not effect the operation of the system. The color of the lights also change based on the speed of the person using the stairs as a bit of an added easter egg.